Abstract: A control circuit for an isolated power converter includes a first sensing circuit that senses a secondary side output voltage and produces a pulse wave modulation (PWM) signal having a duty cycle that is proportional to a value of the secondary side output voltage. The PWM is transferred across the converter isolation barrier to the primary side, and a primary side circuit receives the PWM signal and outputs a control signal. A controller determines the value of the secondary side output voltage from the control signal and uses the value to control primary side power switching devices of the isolated power converter to regulate the secondary side output voltage at a selected value.

Abstract: A controller for an AC-DC converter including a rectifier circuit that converts AC input voltage into DC output voltage uses control logic to control the rectifier circuit according to two or more operating modes. Each operating mode determines a gain of the rectifier circuit. The controller selects an operating mode from the two or more operating modes based on at least one of an AC input voltage value and a required DC output voltage value. The AC-DC converter provides a wide range of DC output voltage with power factor correction. The controller may be used with AC-DC converter topologies such as boost converter, isolated boost converter, PWM converter, LLC resonant converter, and LCC resonant converter.

Abstract: Controllers and methods for controlling a resonant power converter output voltage include operating the power converter according to a control period comprising an on cycle operation mode for a duration T_on that produces a first voltage Vo1 and an off cycle operation mode for a duration T_off that produces a second voltage Vo2. Vo1 is produced using a first switching frequency for a first selected number of switching cycles corresponding to the on time T_on. The converter output voltage or the converter input and output voltages may be sensed and used to determine the switching frequency during the on cycle operation mode and the duration of the off cycle operation mode. The final output voltage of the power converter is regulated to a selected value based on a ration of (T_on):(T_on+T_off). The controllers and methods may be used with power converters in power delivery devices to accept wide input voltage ranges compatible with devices such as cell phones, tablet computers, and notebook computers.

Abstract: A control circuit for an isolated power converter includes a first sensing circuit that senses a secondary side output voltage and produces a pulse wave modulation (PWM) signal having a duty cycle that is proportional to a value of the secondary side output voltage. The PWM is transferred across the converter isolation barrier to the primary side, and a primary side circuit receives the PWM signal and outputs a control signal. A controller determines the value of the secondary side output voltage from the control signal and uses the value to control primary side power switching devices of the isolated power converter to regulate the secondary side output voltage at a selected value.

Abstract: A series circuit includes a capacitor connected in series with output terminals of a power converter. The power converter provides an auxiliary voltage and a controller controls the auxiliary voltage according to a selected function, such that the series circuit behaves as a capacitor, an inductor, or an impedance, based on the selected function. The controller may sense a voltage across the capacitor and use the sensed voltage to control the auxiliary voltage according to the selected function. The series circuit may be connected in parallel with output terminals of an AC-DC converter, wherein the series circuit operates according to a selected mode to produce the auxiliary voltage, and the auxiliary voltage substantially cancels a low frequency AC voltage ripple across the capacitor, such that a substantially pure DC output voltage is delivered to the load.

Abstract: Three-phase single-stage AC-DC converters achieve power factor correction with low phase voltage switch stress. Direct input current sensing is performed to calculate the average input current of the AC-DC converter and implement power factor correction. Embodiments feature high power factor, single stage power conversion, and soft-switching of all switches, resulting in high conversion efficiency in a cost-effective single-stage three-phase structure. The converters have low output voltage ripple without a double line frequency component, which allows non-electrolytic capacitor implementation. The converters are particularly useful in high-power applications such as electric vehicle charging.

Abstract: A power regulator includes an input capacitor connected between a first voltage bus and an intermediate point, an output capacitor connected between a second voltage bus and the intermediate point, a plurality of switches and an inductor connected between the input capacitor and the output capacitor, wherein a source of one switch of the plurality of switches is connected to the intermediate point and a protection device connected between the intermediate point and a third voltage bus.

Abstract: A series circuit includes a capacitor connected in series with output terminals of a power converter. The power converter provides an auxiliary voltage and a controller controls the auxiliary voltage according to a selected function, such that the series circuit behaves as a capacitor, an inductor, or an impedance, based on the selected function. The controller may sense a voltage across the capacitor and use the sensed voltage to control the auxiliary voltage according to the selected function. The series circuit may be connected in parallel with output terminals of an AC-DC converter, wherein the series circuit operates according to a selected mode to produce the auxiliary voltage, and the auxiliary voltage substantially cancels a low frequency AC voltage ripple across the capacitor, such that a substantially pure DC output voltage is delivered to the load.

Abstract: Resonant converters with wide voltage gain ranges are achieved by controlling at least one of the primary side resonant circuit and the secondary side rectifier circuit. A switch is included in at least one of the primary or secondary sides, and control of the switch according to a selected mode determines an output voltage of the resonant converter. Embodiments accommodate wide input and output voltage ranges, and are suitable for use in AC-DC power adapters for portable devices with different voltage requirements, such as cell phones, tablets, and notebook computers, as well as in DC-DC converter applications including electric vehicle power systems.

Abstract: A start-up circuit for a power converter includes a charging circuit that uses a DC bus voltage of the power converter to generate a charging current to charge an energy storage device to a selected voltage and an auxiliary power output circuit including a transformer primary side auxiliary winding. A control circuit controls one or more switches of the start-up circuit and one or more switches of the power converter primary side. The charging current provides power to the control circuit until the auxiliary power is established. The control circuit disables the start-up circuit when the auxiliary power output is established. The start-up circuit has very low standby power consumption and compact size, and is particularly suitable for power converter applications such as power adapters for portable electronic devices.

Abstract: A gallium nitride (GaN) semiconductor device has first and second electrodes connected to a top metal layer disposed in complementary first and second irregular shapes, each irregular shape including a wide connection area at a first end, a tapered area, and a narrow area at a second end. The first and second irregular shapes are arranged adjacent each other along complementary edges such that a gap between the complementary edges is of substantially constant width. The first and second wide connection areas include pads for wire bond or land grid array electrical connections to external circuitry. The first and second irregular shapes for source and drain metal of a field effect transistor (FET) or high electron mobility transistor (HEMT) allows the width of the gate finger to be short so that electrical current injected from the gate can reach all portions of the gate fingers efficiently during high frequency switching, making the topology suitable for high voltage power devices.

Abstract: An LLC power converter comprises a switching stage and a resonant tank, the switching stage configured to switch an input power at a switching frequency to apply a switched power to the resonant tank, and the resonant tank includes a resonant inductor, a resonant capacitor, and a parallel inductance. A transformer has a primary winding connected to the resonant tank and a secondary winding. A synchronous rectifier (SR) switch is configured to selectively switch current from the secondary winding to supply a rectified current to a load. An RC filter includes a filter capacitor and a filter resistor connected across the SR switch, with the filter capacitor defining a filter capacitor voltage thereacross. A rectifier driver is configured to drive the SR switch to a conductive state in response to the filter capacitor voltage being less than a threshold value.

Abstract: A multi-phase LLC power converter comprises a plurality of LLC phases each including a resonant tank and a switching stage. The resonant tank includes a resonant inductor, a resonant capacitor, and a parallel inductance. The switching stage switches an input power at an operating frequency to apply a switched power to the resonant tank, with the switched power approximating an alternating current (AC) waveform having a switching frequency. A secondary-side controller varies the switching frequency to control an output voltage of the multi-phase LLC power converter. A primary-side controller measures primary-side currents, calculates an initial switch-controlled capacitor (SCC) conduction phase angle for each of the LLC phases, and operates an SCC switch in accordance with an SCC conduction phase angle to adjust the capacitance of the resonant capacitor of an LLC phase to cause each of the LLC phases to have equal resonant frequencies.

Abstract: An inductor-inductor-capacitor (EEC) power converter with high efficiency for Electric Vehicle (EV) on-board low voltage DC-DC chargers (LDC) is disclosed. The converter includes a switching bridge with a plurality of bridge switches and configured to generate an output from a direct current input voltage. An EEC tank circuit is coupled to the switching bridge and includes a resonant inductor and a resonant capacitor and a parallel inductor connected between the resonant inductor and the resonant capacitor. The tank circuit is configured to output a resonant sinusoidal current from the output of the switching bridge. At least one transformer has at least one primary winding in parallel with the parallel inductor of the inductor-inductor-capacitor tank circuit and at least one secondary winding. At least one rectifier is coupled to the at least one secondary winding and is configured to output a rectified alternating current.

Abstract: A power converter includes an integrated multi-layer cooling structure. The power converter includes a plurality of printed circuit boards (PCBs) stacked together in a generally vertical arrangement. A liquid cooling mechanism is attached to a lower-most PCB, and high loss circuitry components are attached to an opposite side of the lower-most PCB. Low loss circuitry components are attached to further PCBs. Magnetic components may be attached to the further PCBs. The high loss components are actively cooled by the liquid cooling mechanism and the low loss components and magnetic components are passively cooled. The liquid cooling mechanism may be a cold plate heatsink. The power converter may include intermediate PCBs disposed between the upper-most PCB and the lower-most PCB, with low loss circuitry components attached to the intermediate PCBs.

Abstract: Controllers and methods for controlling a resonant power converter output voltage include operating the power converter according to a control period comprising an on cycle operation mode for a duration T_on that produces a first voltage Vo1 and an off cycle operation mode for a duration T_off that produces a second voltage Vo2. Vo1 is produced using a first switching frequency for a first selected number of switching cycles corresponding to the on time T_on. The converter output voltage or the converter input and output voltages may be sensed and used to determine the switching frequency during the on cycle operation mode and the duration of the off cycle operation mode. The final output voltage of the power converter is regulated to a selected value based on a ration of (T_on):(T_on+T_off). The controllers and methods may be used with power converters in power delivery devices to accept wide input voltage ranges compatible with devices such as cell phones, tablet computers, and notebook computers.

Abstract: Packaging methods and structures for lateral high voltage gallium nitride (GaN) devices achieve electrical isolation while also maintaining thermal dissipation. The electrical isolation reduces or eliminates vertical leakage current, improving high voltage performance. The packages may use or be compatible standards such as JEDEC, which reduces packaging cost and facilitates implementation of the packaged devices in conventional circuit design approaches.

Abstract: In an AC-DC converter having a primary side control circuit, auxiliary power for the control circuit is derived from the converter secondary side through an isolated DC-DC converter. The circuits and methods solve the problem of supplying primary side auxiliary power during light load or no load operation of the AC-DC power converter. Since the output voltage of the AC-DC converter is normally regulated at a fixed level, the auxiliary voltage that is generated by the isolated DC converter is regulated. In some cases the isolated DC-DC converter may not need to be regulated, which simplifies the design and reduces overall cost.

Abstract: A converter includes input voltage terminals, a series circuit connected to the input voltage terminals and including first and second switches connected in series, a transformer including a primary winding and a secondary winding, a resonant tank connected to the series circuit and including the primary winding, an auxiliary switch connected to the series circuit and the resonant tank, output voltage terminals connected to the secondary winding, and a controller that, based on a single control loop and a single control parameter, controls the auxiliary switch with pulse-width modulation and controls the first and second switches with pulse-frequency modulation.

Abstract: A multi-stage, multi-level DC-DC step-down converter includes a first stage and a second stage having two identical cells connected in parallel. The first stage includes an input capacitor, four switches, and one flying capacitor. The two cells of the second stage each include four switches and one flying capacitor, and an output filter. The cells of the second stage are driven at half the switching frequency of the input stage, and provides a step-down ratio of 4:1. A third stage having four cells may be added to achieve a step-down ratio of 8:1, a fourth stage having eight cells may be added to achieve a step-down ration of 16:1, etc., each additional stage including a doubling of the number of cells connected in parallel, with all cells being substantially identical, and each stage operating at a further reduced fraction of the switching frequency. Embodiments are particularly suitable for applications such as a 48V intermediate bus architecture for servers and datacenters.